Electrical switch



Aug. 30, 1938. R. POPP I ELECTRICAL SWITCH Filed Feb. 15, 1955Insulation w v/ b. a g

06271 0; Egg a;

Insulation Patented Aug. 30, 1938 UNITED STATES ELECTRICAL SWITCH RudolflPcpp, Valparaiso, Ind, assignor to McGill Manufacturing Company,Valparaiso, Ind... a

corporation of Indiana Application February 15,

4 Claims.

My invention relates in general to switch mechanisms and more inparticular to a small pullchain type switch ordinarily employed in acanopy or similar installation for controlling a lamp and othercircuits.

An object of my invention is to provide a thin model switch of the abovecharacter, certain in operation and sturdy and compact in construction.

A further object of the invention is to provide a switch of the abovecharacter in a pull-chain type, having circuit connecting mechanismwhich operates with a sharp make-and-break action.

A still further object of my invention is to pro- Vide a switchmechanism composed primarily of punched parts, which is exceptionallylow in cost, yet very efficient in operation.

Other objects and advantages will be apparent from the followingdescription taken with the drawing, in which:

Fig. 1 is a plan View of the assembled switch mechanism.

Fig. 2 is an end elevation of the same.

Fig. 3 is a plan View with the top insulating plate removed, along theline 3-3 of Fig. 2.

Fig. 4 is a cross sectional view along the line 4-4 of Fig. 3.

Fig. 5 is a sectional view along the line 55 of Fig. 4.

Fig. 6 is a detail View of the stationary contacts and contact wheelillustrating particularly the wheel mounting on the rotary axis.

Fig. 7 is a view of the movable switching mechanism showing the variousparts in perspective and disassembled from one another.

Fig. 8 is a detail view in perspective of the threaded mounting stem forthe frame.

In practicing my invention I provide a switch mechanism having a frameincluding upper and lower insulating plates spaced apart by, andsupported on, terminal posts at either end thereof, and a one-piecemounting stem on one side. Stationary contacts are supported on theterminal posts and'connection is completed between them by a rotarymechanism including a contact wheel keyed to a movable axis which inturn is supported between the insulating plates with the contact wheeldriven by the combination of a pawl member keyed to the movable axis andan actuating member carrying a pull chain and having means forengagement with the pawl member to move said axis which in turn rotatesthe contact wheel.

Referring now to the drawing, I provide a switch mechanism having aframe which includes an. upper insulating plate ill and lower insulating1935, Serial No. 6,679

plate ii. The plates are'spaced apart and supported by a pair ofterminal posts I2 and I3 having upstanding lugs I l fitting intoapertures It in each of the plates. Further support is provided in aone-piece threaded stem H as shown 5 particularly in Fig. 8, havingintegral upstanding lugs 58 fitting into corresponding apertures in bothinsulating plates. In the commercial embodiment of the switch verysatisfactory results are obtained with a complete one-piece stem '10member made as a screw machine part. The lugs l8 are integral with asplit head in which the two separated tongues i9 extend back to anannular thread section 20 for receiving an ordinary knurled nut orclamping collar 2|. A seat I1 is provided in the mounting stem to takethe end of the retrieving spring as is shown in Fig. 3, and

as will be hereinafter described. Means are provided in the stem inconcave portions l8, and a bell mouth to prevent the chain from catchingand of course facilitate the action thereof. This construction for thestem provides not only a very strong and inexpensive member, but alsopermits the thread section to extend up to the ordinary housing (notshown) so that only an E5 ordinary thin knurled nut need be employed.

The pair of stationary contact members 22 and 23 are supported on theterminal posts l2 and i3 and extend inwardly as shown inFig. 5.Connecting mechanism rotates between the stationary contacts andincludes an axis or rotor M which comprises a flat piece of insulatingmaterial punched out in the shape shown in Fig. '7 with bearing portions26 at each end and a connecting body portion having a pair of integralspacing ears 2? extending outwardly from the body portion andintermediate the bearing portions 26. A rotary contact wheel 28 with aplurality of cam-shaped teeth 29 on the outer edge is keyed to the rotor24 by means of a rectangular aperture 30. Slight enlargements 3| areprovided in each of two oppositely disposed corners of the aperture topermit a slight play when the wheel is mounted on the axis, and expeditethe contact breaking action when the wheel is rotated as will behereinafter explained. The enlargements are angular in shape and extendfrom substantially the middle of the side of the aperture to the cornerthereof as shown particularly in Figs. 6 and '7. Contact segments 32with an integral connecting strip 33 are mounted on two opposite teeth29 in the usual manner as shown in Figs. 6 and '7. The contact segmentsengage the stationary contacts 22 and 23 to complete a circuit throughthe switch, and the circuit is broken in the usual manner when thecontact wheel is rotated so that the members 22 and 23 lie on theintermediate insulated teeth 29.

In the prior art this general type of pull-chain switch has beenmanufactured in a somewhat bulky structure which is not adaptable tomany of the present day lighting fixture installations. The switchingmechanism is of course largely responsible for the bulky structure inthe prior art devices. There is also some degree of uncertainty in theoperation of the switches due to lack of precision in assembly andadjustment. In my invention I employ metal parts which are stamped toprovide a low cost compact assembly accurate in adjustment and certainand emcient in operation. My actuating mechanism includes a pawl 34stamped in a metal disc with segmental portions sheared on two sides asshown in Fig. 7 to provide a free end 86 for each portion. This free endis curved upwardly to a slight extent and with the slot 3? on the inneredge of the segmental portion, a resiliency results which is effectivein the operation of the switching mechanism as will be hereinafterdescribed. The pawl is keyed to the rotor Ed by means of a rectangularaperture 38 corresponding to the sides of the body portion of saidrotor, and reinforced by a narrow flange 39 sheared in punching out theaperture, and folded back upon each side as shown in Figs. 4 and 5.

The switching mechanism is rotated upon pulling the chain 4i extendingthrough the mounting stem and carried on an actuator member 42, slidablysupported on the pawl 36. The actuator includes an annular body portionwith a round flanged aperture 43 in the center thereof fitting over therotor 24' as shown in Fig. 4. Guide legs M are formed vertically of thering 436 of the body portion, and spaced about the periphery thereof toguide the chain ll which is looped about the actuator from the hookedarm M. Fig. 3 illustrates this construction together with the integralhorizontally disposed chain supporting arm 48. The actuator 62 engagesthe pawl 34 by means of substantially oppositely disposed switch arms19. The arms' ili are curved slightly to give them a very large bearingsurface for engagement with the raised end 36 of the pawl. Thisconstruction makes it possible to use ordinary thin stock for theactuator and insures against the arm slipping under the raised end 36when brought to bear against the same. A vertical lug 5! formed from thebody portion of the actuator adjacent the chain-fastening arm has anextension to carry it into a segmental slit 52 in the top frame plate itThe length of the slit is such as to properly limit the movement of theactuator on the advancing or retrieving operation. The lug 5! also actsas a guide for the chain.

A tightly coiled retrieving spring 53 lies on the ring :36 of the bodyportion of the actuator, with one hooked end 54 lying in the U-shapedprojection 55, and the other end 51 retained against rotary movement byone of the tongues l9 in the head of the mounting stem, and the seat orcavity H in the thread portion of the stem. The entire switch isassembled, with the terminal posts, stationary contacts and mountingstem being positioned on the lower frame plate H. The assembled contactwheel is placed on the rotor 21 and the two assembled on the lowerplate. The pawl 34. is then slipped onto the rotor and rests on the topof the spacing ears 2?. The chain 4| is then pushed through the mountingstem, a distance limited by the enlarged ball 53, and fastened in thehooked arm 41 of the actuator, after which the chain is looped asnecessary about the guide lugs and the actuator slipped over the rotorto rest on pawl 34. As noted, the retrieving spring is then positionedas shown in Fig. 3 and brought to a tension with the elongated end 57retained within the head of the mounting stem. The assembly is then heldin position until the top plate ill is pressed onto the lugs l6 and I8.

Ordinarily in the prior art, in switches of this general type, a loosespring, which is unwieldy and expensive, must be used to provide thenecessary vertical play in the rotary movement of the switch mechanism.I accomplish this by the raised cam-like resilient segments in my pawlmember. The retrieving spring 53 may then be tightly coiled, reducingthe cost of the part and facilitating the assembly of the switch. It isfurther noted that the integral ears 27 on the axis 24 act not only tospace the pawl from the contact wheel, but they also insulate one fromthe other.

As to the operation of the switch, I employ the usual pull chain actionwherein the slidable chain carrying actuator 42 engages the pawl 35through the switch arms 49, and the pawl being keyed to the flat spindlemember 2% turns said axis to rotate the contact wheel 28 which is alsokeyed to the axis. With the angular enlargements 3| in the aperture 30of the wheel, and the spindle 24 rectangular in cross-section, there isa slight play betweeen the spindle and wheel. When the stationarycontacts are at the end of the segmental contacts 32 in the movement ofthe wheel, the spring tension in said stationary contacts snaps thewheel sufiiciently, and the play permits the wheel to move quicklyahead, so that contact is broken simultaneously at each of the segments32.

1e members are still maintained in relative alinement, however, by thestraight portions of the sides of the aperture in the wheel. Thisconstruction and function is important in preventing arcing, and ineffect provides a more precise adjustment in the switch parts, with theresultant more efficient and satisfactory operation of the switch as awhole.

Although I have described my invention in its preferred embodiment, itis understood that I am not limited thereby, but limit the inventiononly by the scope of the appended claims.

I claim:

1. A one-piece tubular stem for a switch having spaced support members,said stem including an externally threaded portion at one end thereof,and a head of larger diameter at the other end thereof, a wide slice ofsaid head being removed to form spaced lugs adapted to fit intocorresponding apertures in the support members of the switch.

2. A one-piece tubular stem for a switch having spaced support members,said stem including an externally threaded portion at one end thereof,and a head at the other end thereof including two portions, one oflarger diameter than the other; a wide slice of said head being removedto form spaced upstanding lugs from the larger portion thereof forinsertion in corresponding apertures in said support members, and toform spaced rests on the smaller portion of the head for resting againstsaid support members.

3. A one-piece mounting stem for an electric switch having spaced apartframe members, said stem including an externally threaded portion at oneend for receiving a mounting nut, and a head at'the other end split toprovide spaced lugs for fitting into corresponding apertures of theframe and within the threaded portion, and a switch actuating means seatadjacent the outer end of the threaded portion.

'4. A one-piece mounting member for a switch including actuatingmechanism havin a return spring and operating means, said mountingmember comprising a threaded annular neck with an integral seat for the.return spring of the switch at one end of the neck and an integral seatfor the operating means to limit the movement thereof at the other endof the neck, and a securing head for the mounting member integral withthe neck and extending longitudinally from the return spring seat endthereof to an open end with securing studs extending upwardly anddownwardly at the open end with a relatively wide slice being removedfrom said head intermediate the

